The present invention relates generally to opto-electronic light sources. More particularly, the invention relates to optical source modules and a method for making them, the modules comprising a semiconductor laser light source and a collimating or focusing lens element combined into a compact and efficient photonic (optical) source module. The module offers the advantages of simple but rugged construction in combination with controlled and reproducible light output characteristics. These advantages stem from the method of construction employed, which offers economical and rapid but accurate permanent alignment of the optical source and lens elements of the modules.
Opto-electronic light sources incorporating laser diodes are well known, being used extensively in applications such as bar code scanners. U.S. Pat. No. 4,923,281, for example, describes a laser diode focusing module useful for bar code scanning applications wherein the output from a semiconductor laser diode is collimated and clipped by a combination of a convergent lens and a mask or stop to provide a laser beam of controlled alignment and shape.
However, these and other existing designs for collimated laser source modules are expensive to produce and exhibit output characteristics which are somewhat variable and hard to control. The use of lens retaining springs and multi-part housing components, in particular, increases manufacturing cost and limits the maximum device reproducibility and physical durability which may be achieved.
It is therefore a principal object of the present invention to provide an optical source module which is both simple in design and rugged in construction.
It is a further object of the invention to provide optical source module designs which offer optical beam characteristics which are consistent and repeatable.
It is a further object of the invention to provide a method for manufacturing an optical source module of improved quality at reduced cost.
Other objects and advantages of the invention will become apparent from the following description thereof.